Both men were indicted Friday on charges stemming from those meetings.
Syed Haris Ahmed and Ehsanul Islam Sadequee, both U.S. citizens who grew up in the Atlanta area, met with at least three other targets of ongoing FBI terrorism investigations during a trip to Canada in March 2005, an FBI agent's affidavit said.
The affidavit said the men discussed attacks against oil refineries and military bases and planned to travel to Pakistan to get military training at a terrorist camp, which authorities said Ahmed then tried to do.
Ahmed, who was indicted on suspicion of giving material support to terrorism, was being held at an undisclosed location. He waived his right to arraignment and pleaded not guilty. His indictment, which carries a maximum sentence of 15 years in prison and a fine of up to $250,000, was returned under seal on March 23 and unsealed by the court Thursday.
Ahmed's court-appointed attorney, Jack Martin, did not return messages left seeking comment.
Sadequee, 19, who is accused of making materially false statements in connection with an ongoing federal terrorism investigation, was arrested in Bangladesh and was en route to New York City to be arraigned. Several messages left with his sister and attorney were not immediately returned.
"There is no imminent threat," said FBI Special Agent Richard Kolko, a spokesman in Washington.
Federal authorities declined to comment further, citing an ongoing investigation.
"We take it very seriously — it's national security," said Department of Justice spokesman Bryan Sierra.
Ahmed, who was born in Pakistan and moved with his family to the U.S. about 10 years ago, said he met Sadequee at a mosque in Atlanta, the affidavit from FBI agent Michael Scherck said. Sadequee, whose family came from Bangladesh, was born in Virginia and lived with his family in Roswell, Ga.
Authorities said the two men spent several days in Canada, where they met with others being investigated by the terrorism task force.
Sadequee is accused of lying about the trip when he was interviewed at John F. Kennedy International Airport in August as he was about to leave for Bangladesh. The affidavit said Sadequee told investigators he had traveled alone in January to visit an aunt.
When Sadequee's suitcase was searched at JFK, agents found a CD-ROM containing encrypted files that the FBI has been unable to decode and a map of the Washington area hidden in the lining, the affidavit said.
One day later, federal agents interviewed Ahmed, who was coming back from a monthlong trip to Pakistan, at Atlanta's Hartsfield-Jackson International Airport. He said he had gone to Toronto with Sadequee in March and that they had stayed with another conspirator, according to the affidavit.
Federal agents found that money for both men's 2005 bus trip from Atlanta to Toronto was withdrawn from Sadequee's account. They had tickets to depart on March 6 and return seven days later. But the affidavit says they returned to the U.S. moments apart on March 12.
In March 2006, Ahmed then told agents they had met with extremists and plotted how to disrupt military and commercial communications and traffic by disabling the Global Positioning System, the affidavit said. He was arrested March 23.
By Giovanna Dell-Orto